Macro calculator for coaches
Work out a client's starting calories, protein, fat and carbs. Every formula and source is on the page.
Calculator
Starting target
1,630 kcal a day: 125 g protein, 45 g fat, 181 g carbohydrate.
- Height and weight: 168 cm and 78 kg, or 5 ft 6 in and 172 lb.
- Resting rate: 10 × 78 + 6.25 × 168 − 5 × 34 − 161 = 1,499 kcal.
- Maintenance: 1,499 × 1.375 (lightly active) = 2,061 kcal.
- Goal, lose 0.5 % a week: 0.39 kg × 7,716 kcal ÷ 7 = −430 kcal, so 1,630 kcal to the nearest 10.
- Protein: 1.6 g × 78 kg = 125 g, or 500 kcal.
- Fat: 25 % of 1,630 kcal ÷ 9 = 45 g, or 405 kcal.
- Carbs: (1,630 − 500 − 405) ÷ 4 = 181 g.
A starting point for a professional, not medical advice. Check it against two weeks of weigh-ins and adjust.
How the numbers are worked out
Resting rate. The Mifflin-St Jeor equation (Mifflin and others, 1990), built from 498 healthy adults aged 19 to 78 with measured resting energy expenditure. For women, 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161. For men the last term is + 5. A 2005 systematic review found it the most reliable of the four common equations, within 10 % of measured for most people.
Activity. The resting rate times one of five conventional factors. They are a convention rather than a finding; the FAO/WHO/UNU report puts measured physical activity levels at 1.40 to 1.69 for a sedentary or light lifestyle, 1.70 to 1.99 for an active one and 2.00 to 2.40 for a vigorous one.
| Level | A normal week | Factor |
|---|---|---|
| Sedentary | Desk job, little or no exercise | × 1.2 |
| Lightly active | Light exercise 1 to 3 days a week | × 1.375 |
| Moderately active | Exercise 3 to 5 days a week | × 1.55 |
| Very active | Hard exercise 6 or 7 days a week | × 1.725 |
| Extra active | Hard daily training and a physical job | × 1.9 |
Goal. Fat loss is set as a rate: 0.5 or 1 % of body weight a week, the range Helms and others (2014) give for keeping muscle, converted at 3,500 kcal a pound of fat (about 7,716 kcal a kg) and divided by seven. Muscle gain adds 10 % to maintenance, the low end of the 10 to 20 % surplus in Iraki and others (2019). The day's target is rounded to the nearest 10 kcal.
Protein. Grams per kg of body weight, 1.6 by default: Morton and others (2018) found gains in fat-free mass stop rising at about 1.62 g/kg a day. The ISSN position stand (Jäger and others, 2017) gives 1.4 to 2.0 g/kg for people who exercise, and the PROT-AGE group (Bauer and others, 2013) at least 1.0 to 1.2 for people over 65.
Fat and carbohydrate. Fat takes a share of the calories, 25 % by default, inside the 15 to 30 % Helms and others give. Carbohydrate is what is left. Protein and carbohydrate count 4 kcal a gram and fat 9.
This is a starting point for a professional, not medical advice. The first two weeks of weigh-ins are the real calculation: see How to calculate a client’s calorie needs from their intake.
Sources
- A new predictive equation for resting energy expenditure in healthy individuals(opens in new tab)Mifflin and others, The American Journal of Clinical Nutrition (1990)
- Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review(opens in new tab)Frankenfield and others, Journal of the American Dietetic Association (2005)
- Human energy requirements: report of a Joint FAO/WHO/UNU Expert Consultation(opens in new tab)FAO, WHO and UNU, chapter 5, Table 5.3 (2004)
- Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation(opens in new tab)Helms and others, Journal of the International Society of Sports Nutrition (2014)
- Nutrition recommendations for bodybuilders in the off-season: a narrative review(opens in new tab)Iraki and others, Sports (2019)
- A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults(opens in new tab)Morton and others, British Journal of Sports Medicine (2018)
- International Society of Sports Nutrition Position Stand: protein and exercise(opens in new tab)Jäger and others, Journal of the International Society of Sports Nutrition (2017)
- Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group(opens in new tab)Bauer and others, Journal of the American Medical Directors Association (2013)
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The calculator, answered.
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A systematic review of the four equations most used in practice (Frankenfield and others, 2005) found Mifflin-St Jeor predicted resting metabolic rate within 10 % of measured in more people than any other, with the narrowest error range. It is still an estimate, and some people fall outside that band.
The five factors (1.2, 1.375, 1.55, 1.725 and 1.9) are the convention most calculators use with Mifflin-St Jeor. They are not in Mifflin's paper, and no single study derived them. For comparison, the FAO/WHO/UNU report classes a sedentary or light lifestyle at a physical activity level of 1.40 to 1.69, so the sedentary factor here is on the low side. Two weeks of weigh-ins will tell you more than the choice of factor.
Morton and others (2018) pooled 49 trials and found gains in fat-free mass stopped rising at about 1.62 g/kg a day, with a wide confidence interval. For a lean client in a deficit, Helms and others (2014) give 2.3 to 3.1 g per kg of lean body mass. Change the field to the number you use. Our article Protein for fat loss and muscle gain has the detail.
As a rate of loss, not a fixed number of calories: 0.5 or 1 % of body weight a week, the range Helms and others (2014) give to keep muscle. The weekly loss is converted at 3,500 kcal a pound of fat (about 7,716 kcal a kg) and spread over seven days. The same review warns that this static sum does not model how the body adapts, so check the target against the scale.
No. It is a starting point for a coach or a dietitian, not a diagnosis or a prescription. If a client is pregnant, under 18, has kidney disease, diabetes, a thyroid condition, a history of disordered eating or takes medication that affects weight, refer them to their doctor or a registered dietitian first.
No. The calculator runs in your browser and sends nothing anywhere. Close the page and the numbers are gone.